Is it obligatory to wear a qamis, or is it permissible to wear trousers, and what are the conditions for them if they are permissible?

The Shari'ah broadens the scope concerning customs, and it urges the Muslim to wear what the people of his country are accustomed to, as long as the clothing covers the 'awrah, and not to deviate from their common attire. This is because departing from people's customs in dress may lead to embarrassment, hardship, boasting, and showing off. Moreover, it is not permissible to attribute to the religion what is not part of it. The Permanent Committee for Issuing Fatwas has issued a fatwa stating that the basic principle regarding types of clothing is permissibility, with the exception of what is prohibited by sharia evidence. The clothing known as "trousers" (بنطلون) and "shirt" (قميص) is not exclusive to disbelievers; rather, it is common attire among both Muslims and disbelievers.